Abrupt climate change during the Middle Stone Age triggered technological innovation in early modern human populations, reports research published this week in Nature Communications. Examples include symbolic expression through engraved ochres, stone and bone tools, shell jewellery and plant bedding constructions.

Modern humans originated in Africa during the Middle Stone Age, which lasted from 280,000 to 30,000 years ago. Archaeological studies have documented several abrupt pulses of major technological advance, reflecting the emergence of modern behaviour, but there has been an extended debate about the factors behind cultural evolution and the emergence of modern human behaviours. Martin Ziegler and colleagues examine marine sediment core data off the Eastern Cape coast in South Africa, holding a record of the climate events during those pulses of technological innovation. Their results suggest a direct link between abrupt climate change and the development of cultural complexity in early humans.

These climate fluctuations recorded on marine sediments relate to changes in the Atlantic Ocean circulation, which led to fluctuations between dry conditions to more humid conditions in South Africa, and potentially to the creation of favourable environmental conditions for humans. This strongly implies that innovational pulses of early modern human behaviour were climatically influenced and linked to favourable humid conditions in southern Africa.